Q&A – Is it okay to feel physically sick (not ill) after the workout from the effort sometimes?

Yes, it is okay. That feeling comes from an increased lactate level in the blood stream.When you work out hard and heavy, you go into glycolysis, producing energy from glucose directly without using oxygen. That results in an accumulation of the final product called pyruvate which is readily transformed into lactate. That lactate then, in high amounts, can make you feel nauseous and even lead to vomiting.

Especially after working big muscle groups, this is more prevalent (usually legs and back). And it’s a sign of a hard workout to the limit and nothing that should be avoided if you want to progress.

It’s not dangerous, nor bad for the health. The liver learns to deal with it more efficiently after stressing it a few times. There is no supplement that can prevent that nausea. Very light physical activity (like walking around) helps other muscles to burn lactate as fuel, thus reducing the levels of lactate in the bloodstream.